JPWO2019207793A1 - Elastically deformable container with excellent rupture durability - Google Patents

Abstract

The elastically deformable tubular container of the present invention is an elastically deformable tubular container having an opening, a closed portion with a closed tip, and an intermediate portion connecting the opening and the closed portion, and the intermediate portion is The diameter of the reduced diameter portion has a gradually reduced diameter portion, and the diameter of the portion where the diameter of the reduced diameter portion is most reduced is 70 to 95% of the diameter of the portion having the largest diameter of the container. The vertical cross-sectional shape passing through the central axis of is formed by a continuous curve without passing through a straight line portion, or is formed by two or more curves including one or more straight line portions, and the straight line portion is tangent to the curve. Is forming. [Selection diagram] Fig. 1

Description

The present invention relates to an elastically deformable tubular container having excellent durability against rupture due to expansion, and particularly to a tubular container having excellent durability against rupture due to expansion and not significantly reducing the storage capacity.

Synthetic rubber such as natural rubber and polyurethane rubber, or high molecular weight elastomer has excellent flexibility and elasticity, is hard to tear even if it is thin, and has excellent watertightness and airtightness. Therefore, condoms, urine collection tools, gloves, probes It is used for a wide range of purposes such as covers. In addition, its compact form, expandability, and large capacity allow it to be used as a water storage container in the event of a disaster.

For example, Japanese Patent Application Laid-Open No. 2002-001373 describes an inflatable container using a rubber film used as a simple treatment tank, a disposable treatment tank, an inflatable rubber membrane container, etc., and Japanese Patent Application Laid-Open No. 2017-123999 describes a condom. Men's urine storage device using the material of is described. However, when a material such as natural rubber, synthetic rubber, or a polymer elastomer is used as a condom or an expandable container, further improvement in pressure resistance against rupture due to expansion is required.

In addition, JIST9111 defines pinhole detection test (water leakage test) and burst test (measurement of burst capacity and burst pressure) as standards for latex condoms, and these tests are stable in the manufacture of condoms. It is also important to pass.

JP-A-2002-001373 Japanese Unexamined Patent Publication No. 2017-12399

Therefore, an object of the present invention is to provide an elastically deformable tubular container that is excellent in durability against rupture due to expansion and has a large accommodating capacity, and in particular, is excellent in durability against rupture due to expansion and at the same time. It is to provide a condom that does not significantly reduce the capacity.

As a result of diligent research in view of the above object, the present inventors reduced the diameter of the middle part of the elastically deformable tubular container, and the ratio of the diameter of the part where the diameter was the smallest to the diameter of the part where the diameter of the container was the largest. It was found that the bursting durability is improved and a container with a large capacity can be obtained by forming the part where the diameter of the vertical cross-sectional shape of the tubular container is the smallest by a curve while keeping the temperature within a specific range. , The present invention has been completed.

That is, the elastically deformable tubular container of the present invention is an elastically deformable tubular container having an opening, a closed portion with a closed tip, and an intermediate portion connecting the opening and the closed portion, and the intermediate portion. Has a reduced diameter portion whose diameter is gradually reduced, and the diameter of the portion where the diameter of the reduced diameter portion is most reduced is 70 to 95% of the diameter of the portion where the diameter of the container is the largest, and the diameter of the reduced portion is 70 to 95%. The vertical cross-sectional shape passing through the central axis of the diameter portion is formed by two or more continuous curves without passing through a straight portion, or is formed by two or more curves including one or more straight portions, and the straight portion is formed. It forms a tangent line with the curve.

The vertical cross-sectional shape passing through the central axis of the reduced diameter portion is preferably formed by connecting two or more arcs at inflection points.

In one embodiment of the present invention, the vertical cross-sectional shape passing through the central axis of the inflection point of the container is a first arc that is continuously arranged and is convex to the outside of the container, and is convex to the inside of the container. A second arc and a third arc that is convex to the outside of the container are formed by connecting to adjacent arcs at inflection points.

In one embodiment of the present invention, the vertical cross-sectional shape passing through the central axis of the reduced diameter portion of the container is a first arc that is continuously arranged and is convex to the outside of the container, and is convex to the inside of the container. The second arc and the third arc that is convex to the outside of the container are connected to the adjacent arc via a straight line portion, and the straight line portion forms a tangent line to the adjacent arc. ..

In one embodiment of the present invention, the ratio (R) of the radius (R) of the arc forming the portion where the diameter of the reduced diameter portion of the container is most reduced to the diameter (d) of the portion where the diameter of the reduced diameter portion is most reduced. / D) is 8 to 25, 10 to 18, or 11 to 15.

In one embodiment of the invention, the tubular container is a condom.

FIG. 1 shows a front view of the condom of the present invention, which has a reduced diameter portion in the middle portion and the contour line of the reduced diameter portion is formed by a continuous curve without passing through a straight portion. Is. FIG. 2 shows a plane (b) of the present invention, which has a reduced diameter portion in the middle portion and the contour line of the reduced diameter portion is formed by a continuous curve without passing through a straight portion. It is a figure. FIG. 3 shows the condom of the present invention having a reduced diameter portion in the middle portion and the contour line of the reduced diameter portion formed by a continuous curve without passing through a straight portion, (c) bottom surface. It is a figure. FIG. 4 shows the present invention in which a reduced diameter portion having a reduced diameter is provided in the middle portion, and the vertical cross-sectional shape passing through the central axis (S) of the reduced diameter portion is formed by a continuous curve without passing through a straight portion. It is a vertical sectional view which shows a condom. FIG. 5 is a graph showing the relationship between the reduction rate of the diameter of the container and the burst pressure and the burst capacity of the container. FIG. 6 is a front view (a) showing a conventional condom in which an intermediate portion is formed by a straight contour line. FIG. 7 is a plan view (b) showing a conventional condom in which an intermediate portion is formed by a straight contour line. FIG. 8 is a bottom view (c) showing a conventional condom in which an intermediate portion is formed by a straight contour line. FIG. 9 is a front view (a) showing a conventional condom in which a reduced diameter portion having a reduced diameter is formed by a straight contour line. FIG. 10 is a plan view (b) showing a conventional condom in which a reduced diameter portion having a reduced diameter is formed by a straight contour line. FIG. 11 is a bottom view (c) showing a conventional condom in which a reduced diameter portion having a reduced diameter is formed by a straight contour line.

In the present specification, the term "cylindrical" means a hollow tubular shape, and is not limited to a cylindrical shape. A part of the tubular structure may have a constriction or a bulge. Good. The "longitudinal section" of the tubular container means the cross section when the container is cut in the longitudinal direction (axial direction), and the "diameter" of the tubular container is the cross section of the container (cut at right angles to the axial direction). When the cross section), it means the diameter or the maximum diameter. The "capacity" of a container means the maximum capacity of the container that the container can stably contain. The "burst capacity" of a container means the maximum capacity of air that can be contained before the container bursts, as measured by injecting air into the container. The "capacity" of the container increases as the "burst capacity" increases. The "burst pressure" of a container means the pressure at which the container bursts, which is measured by injecting air into the container. The "intermediate portion" of a container means an intermediate portion connecting an opening and a closing portion of the container. The “diameter-reduced portion” means a portion having a reduced diameter located between the opening and the closing portion of the container. The "reduced diameter portion" may be a part of the "intermediate portion" of the container, or may be the entire "intermediate portion". The "opening" means the entrance / exit of the tubular container, and the "closed portion" means the closed portion of the tip of the tubular container. Also, "mm" means millimeters and "g" means grams.

For a tubular container made of an elastically deformable material, when a fluid such as liquid or gas is injected into the container and the opening is sealed with packing, the middle part of the tubular container is most likely to expand, and the middle part becomes It expands into a spindle shape. The intermediate portion of the tubular container expanded in a spindle shape in this way has a larger strain than other portions and is likely to burst.

FIG. 6A is a front view showing a conventional condom in which the middle portion is formed by a straight contour line. The condom shown in FIG. 6A is formed by two parallel straight lines whose intermediate contour lines are parallel to the central axis (S). When a liquid or gas is injected into the condom and the opening is sealed with packing, the middle part of the condom expands into a spindle shape, and the middle part of the condom is liable to burst. This type of condom has a large capacity but has the disadvantage of low pressure resistance.

On the other hand, when the diameter of the middle portion of the container is reduced (reduced in diameter), the expansion of the middle portion of the container is suppressed, and the upper and lower portions of the container are likely to expand. The stress-strain curve of an elastic vessel increases in inclination (change in stress with respect to change in strain) as the strain increases. The low-strain region tends to expand at the initial stage, but when it expands beyond a certain level, the strain increases, and the stress rapidly increases and it becomes difficult to deform. When the diameter of the middle part of the container is reduced, the upper part and the lower part expand preferentially over the middle part at the initial stage, but when the strain increases and the stress increases accordingly, the middle part tends to expand. Therefore, by appropriately adjusting the diameter of the container, the tubular container expands substantially evenly, and excellent pressure resistance can be exhibited.

FIG. 5 shows the relationship between the reduction rate of the diameter of the container and the burst pressure and the burst capacity of the container. As shown in FIG. 5, as the reduction rate of the diameter of the container (body) increases, the burst pressure of the container increases, but the burst capacity of the container decreases significantly. When the diameter of the container is reduced, the burst pressure of the container and the burst capacity of the container change in opposite directions, and a shrinkage ratio satisfying both cannot be obtained. As described above, it is difficult to achieve a container having improved pressure resistance and not reducing the accommodating capacity only by reducing the diameter of the container.

FIG. 9A is a front view showing a conventional condom in which a portion having a reduced diameter is formed by a straight contour line. In this condom, the contour line of the reduced diameter portion of the condom is formed by a straight line parallel to the central axis (S) of the condom, and from the transition portion from the vicinity of the closed portion of the condom to the reduced diameter portion and the vicinity of the opening of the container. The transition portion to the reduced diameter portion is formed by a curved line. That is, the connection portion between the reduced diameter portion of the container and the transition portion to the closed portion and the connecting portion between the reduced diameter portion of the container and the transition portion to the opening portion are straight and curved connections. It has been found by the studies of the present inventors that the pressure resistance of a container having such a shape is improved by providing a reduced diameter portion in the middle portion of the container, but the storage capacity of the container is reduced.

The present inventors greatly reduce the storage capacity of the container by providing a reduced diameter portion in the middle portion of the tubular container and adjusting the contour line (or the vertical cross-sectional shape passing through the central axis) of the reduced diameter portion. It was found that the pressure resistance of the container could be significantly improved without the need for it. The container of the present invention has an opening, a closed portion with a closed tip, and an intermediate portion connecting the opening and the closed portion, and the intermediate portion has a reduced diameter portion whose diameter is gradually reduced. The contour line (or the vertical cross-sectional shape passing through the central axis) of the part where the diameter of the reduced diameter part is the smallest is formed by a curve, and the diameter of the part where the diameter of the reduced diameter part is the smallest is the part where the diameter of the container is the largest. It is preferably 70 to 95%, more preferably 80 to 95%, and even more preferably 85 to 95% with respect to the diameter of the opening (for example, the diameter of the opening).

The middle portion of the tubular container may be entirely formed by a reduced diameter portion, or may have a non-reduced diameter portion having a constant diameter on the opening and / or closing portion side. Further, the diameter-reduced portion is preferably one in one tubular container except for the closed portion.

One container according to the present invention has a reduced diameter portion in the middle portion, and the contour line (or the vertical cross-sectional shape passing through the central axis) of the reduced diameter portion is formed by two or more continuous curves without passing through a straight line portion. Will be done. The curved portion is formed by connecting, for example, two or more arcs, for example, three arcs. When the curved portion is formed by connecting two or more arcs, the size of each arc may be the same or different. In one embodiment of the present invention, the contour line (or the vertical cross-sectional shape passing through the central axis) of the reduced diameter portion is formed by connecting two or more arcs having different convex directions at an inflection point. For example, the longitudinal cross-sectional shape that passes through the central axis of the inflection point of the container is a continuous first arc that is convex to the outside of the container, a second arc that is convex to the inside of the container, and the container. A third arc that is convex to the outside of the is formed by connecting the adjacent arcs at the inflection points.

Another container according to the present invention has a reduced diameter portion in the middle portion, and the contour line (or the vertical cross-sectional shape passing through the central axis) of the reduced diameter portion is formed by two or more curves including one or more straight lines. , The straight part forms a tangent to the curve. For example, the vertical cross-sectional shape that passes through the central axis of the reduced diameter portion is
A first arc that is convex to the outside of the container, a second arc that is convex to the inside of the container, and a third arc that is convex to the outside of the container, which are arranged continuously, are adjacent arcs. It is formed by connecting via a straight line portion and forming a tangent line with an adjacent arc.

In the tubular container of the present invention, the vertical cross-sectional shape of the reduced diameter portion is formed by a gentle continuous curve without passing through a straight portion, or the curve is connected so that the straight portion is a tangent to the curve. As a result, both improvement of pressure resistance and prevention of reduction in storage capacity are achieved.

In the vertical cross-sectional shape of the container, it is desirable that the radius of the arc forming the reduced diameter portion of the container is sufficiently larger than the diameter of the portion where the diameter of the reduced diameter portion is most reduced. Specifically, the ratio (R / d) of the radius (R) of the arc forming the portion where the diameter of the reduced diameter portion is most reduced and the diameter (d) of the portion where the diameter of the reduced diameter portion is most reduced is preferable. Is 8 to 25, more preferably 10 to 18, and even more preferably 11 to 15.

A preferred embodiment of the container of the present invention will be described with reference to FIGS. 1-3. FIG. 1A shows a condom of the present invention having a reduced diameter portion (reduced diameter portion) in an intermediate portion and the contour line of the reduced diameter portion formed by a continuous curve without passing through a straight portion. It is a front view. An arc that is convex to the outside of the condom is preferably connected to the vicinity of the closed portion at the tip of the condom so as to form a tangent line with a straight portion in the vicinity of the closed portion, and the diameter is gradually reduced by the arc. On the way, it is inverted into an arc that is convex inward of the condom through the inflection point (P), further reduced, and touches a straight line parallel to the central axis (S) of the condom. This contact (Q) is the portion where the diameter is the smallest. When it exceeds the contact point, the diameter gradually expands, and in the middle, it reverses again to an arc that is convex to the outside of the condom through the inflection point (P'). The inverted arc is connected so that its diameter gradually expands and preferably forms a tangent to the straight portion on the opening side of the condom. As described above, in the condom of the present invention, the contour line (or the vertical cross-sectional shape passing through the central axis (S)) of the reduced diameter portion is formed by a continuous curve without passing through a straight line portion.

In another preferred embodiment of the container of the present invention, in the condom shown in FIG. 1 (a), the arc and the arc are connected not by an inflection point but by a straight line portion forming a tangent to the arc. An arc that is convex to the outside of the condom is preferably connected to the vicinity of the closed portion at the tip of the condom so as to form a tangent line with a straight portion in the vicinity of the closed portion, and the diameter is gradually reduced by the arc. On the way, the straight line portion is connected to the arc so as to form a tangent line with the arc that is convex on the outside of the condom, and further, the arc that is convex on the inside of the condom is connected so as to form a tangent line with this straight line portion. The arc that is convex inside the condom is further reduced and touches a straight line parallel to the central axis (S) of the condom. This contact (Q) is the portion where the diameter is the smallest. When it exceeds the contact point, the diameter gradually increases, and the straight part is connected to the arc so as to form a tangent line with the arc that is convex inside the condom on the way, and further to the outside of the condom so as to form a tangent line with this straight part. Convex arcs connect. The inverted arc is connected so that its diameter gradually expands and preferably forms a tangent to the straight portion on the opening side of the condom.

The diameter of the condom opening is typically about 30-40 mm, more appropriately about 31-37 mm, more preferably 32-37 mm. The diameter of the portion where the diameter of the condom of the present invention is most reduced is usually about 22 to 38 mm, preferably about 26 to 34 mm. The radius of the arc forming the contour of the reduced diameter portion of the condom is usually about 330 mm to 470 mm, preferably about 360 to 440 mm, with the radius of the arc forming the portion having the smallest diameter reduced.

The material constituting the tubular container of the present invention is not particularly limited as long as it is an elastically deformable material having expandability. Examples of materials constituting the tubular container include natural rubber and synthetic rubber (isoprene rubber, butadiene rubber, styrene / butadiene rubber, chloroprene rubber, nitrile rubber, polyisobutylene rubber, polyurethane rubber, silicon rubber, ethylene propylene rubber, and chloro. Examples thereof include sulfonated polyethylene rubber, acrylic rubber, fluororubber, epichlorohydrin rubber, etc.), thermoplastic elastomers (polystyrene-based, polyolefin-based, vinyl chloride-based, polyurethane-based, polyester-based, polyamide-based, polybutadiene-based, etc.).

The tubular container of the present invention can be manufactured by a known technique or a combination thereof. For example, a method of immersing the mold of the container in the raw material liquid and adhering the raw material to the mold for molding, a method of blow molding in the mold, and the like can be mentioned. In one embodiment when the container is a condom, first, a mold in the shape of a condom is made (the mold is made of a material such as glass or stainless steel), and this mold contains natural rubber, synthetic rubber, a polymer elastomer, and the like. Immerse in raw material solution. The mold is pulled up from the raw material liquid, the raw material liquid adhering to the mold is heated and dried, and further treated with swelling, vulcanization, etc., and the dried product is removed from the mold to make a condom (diameter of the obtained condom). Shrinks about 5% of the diameter of the mold). A ring is provided at the opening of the condom. Condoms are usually rolled up and stored in a packaged form.

The condom may contain other components, if necessary, or may be coated with other components such as a lubricant. Examples of other components that can be contained include vulcanizing agents, vulcanization aids, vulcanization accelerators, antioxidants, stabilizers and the like. The vulcanizing agent is not particularly limited, and examples thereof include sulfur, sulfur-containing compounds, and peroxides. The vulcanization aid is not particularly limited, and examples thereof include inorganic compounds such as zinc oxide and magnesium oxide, and organic compounds such as stearic acid and amines. The vulcanization accelerator is not particularly limited, but is limited to thiurams (tetramethylthium monosulfide, tetramethylthiuram disulfide, etc.), dithiocarbamates (zinc diethyldithiocarbamate, zinc dibutyldithiocarbamate, zinc dibenzyldithiocarbamate, diisononyldithiocarbamine). Zinc acid acid, etc.), mercaptobenzothiazoles (2-mercaptobenzothiazole, mercaptobenzthiazole zinc, etc.), dithiocarbamate (zincdiethyldithiocarbamate, disulfide-n-butyl-dithiocarbamate, etc.), sulfenamides (2, 2-Dithiobisbenzothiazole-2-sulfenamide, N-cyclohexylbenzothiazole-2-sulfenamide, etc.), diphenylguanidine, thiocarbonates (trithiocarbonate, etc.), guanidines (diphenylguanidine, di-o, etc.) − Trilguanidine, etc.), thiourea, etc. can be mentioned.

The anti-aging agent is not particularly limited, but is a hindered phenolic compound (4-[[4,6-bis (octylthio) -1,3,5-triazine-2-yl] amino] -2,6-di. -Tert-butylphenol, 2,4-bis [(octylthio) methyl] -o-cresol, butylation reaction product of p-cresol and dicyclopentadiene, butylated phenol, octylylated phenol, etc.), bisphenol compounds (4) , 4'-thiobis (3-methyl-6-tert-butylphenol), etc.) and the like. The stabilizer is not particularly limited, and examples thereof include potassium hydroxide, dialkylamine, higher fatty alcohol, lauric acid soap, ethylenediaminetetraacetic acid and the like. The lubricant is not particularly limited, but is limited to silicone oil, lanolin, α-olefin, polyalkylene glycol, polyol ester, liquid paraffin, paraffin wax, fatty acid, higher alcohol, nonionic, anionic or cationic surfactant. Examples include agents.

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

The condoms of Examples and Comparative Examples were produced under the following conditions.
Raw materials: Natural rubber, sulfur (vulcanizing agent), zinc oxide (vulcanization aid), bisphenol compound (anti-aging agent), and water-based compounding raw materials were used.
Conditions: Glass molds corresponding to each of the present invention and the comparative example were used.
The glass mold was immersed in the raw material liquid (immersion depth 230 mm), the mold was pulled up from the raw material liquid, dried, and then swelled and post-vulcanized.

(Example 1)
Using a glass mold that imitates a condom having a vertical cross-sectional shape shown in FIG. 4, the total length excluding the protrusion (T) (semen reservoir) is about 180 mm, and the diameter of the opening is about 33 mm. Was produced. The condom weighed about 0.95 g and was about 0.044 mm thick. The shape of the obtained condom is described below. The condom is connected so as to form a tangent line with a convex arc on the outside of the condom having a radius (R) of about 400 mm at a position (diameter: about 33 mm) about 30 mm from the tip of the closed portion, and this radius (R) is about about 400 mm. The diameter is gradually reduced by the arc of 400 mm, and the direction of the curve is reversed with the position (diameter: about 32.75 mm) about 60 mm from the tip of the closed part as the turning point (P), and the radius (R) of the condom of about 400 mm. The inwardly convex arc continues to gradually reduce the diameter. The arc whose direction is reversed has a line parallel to the central axis (S) of the condom as a tangent line, and a contact point (Q) is about 90 mm from the tip of the closed portion. The position about 90 mm from the tip of the closed portion is the part where the diameter is the smallest (diameter: about 30.5 mm). The diameter of the arc that has passed the contact point is gradually expanded, and the direction of the curve is reversed again with the position (diameter: about 32.75 mm) about 120 mm from the tip of the closed portion as the inflection point (P'). The arc that is convex to the outside of the condom with a radius (R) of about 400 mm that is inverted again becomes the same diameter as the opening at about 150 mm, and the area between about 150 mm and the opening is almost parallel to the central axis (S) of the condom. A contour line is formed by a straight line and is connected to the vicinity of the opening.

(Comparative Example 1)
Using a glass mold imitating the shape of the condom shown in FIGS. 6 to 8, a condom having a total length of about 180 mm and a diameter of about 33 mm excluding the protrusion (T) (semen reservoir) was produced. The condom weighed about 0.95 g and was about 0.044 mm thick. The shape of the obtained condom is formed by a straight contour line in which the diameter of the opening is constant and continues to the vicinity of the closing portion, and has no reduced diameter portion in the intermediate portion.

(Comparative Example 2)
Using a glass mold that imitates the shape of the condom shown in FIGS. 9 to 11, a condom having an overall length of about 180 mm excluding protrusions (T) (semen reservoir) and an opening diameter of about 33 mm. Made. The condom weighed about 0.95 g and was about 0.044 mm thick. The shape of the obtained condom is described below. The diameter of the condom starts to decrease at a position (diameter: about 36 mm) of about 40 mm from the tip of the closed part, becomes about 29 mm mm at a position of about 65 mm from the tip of the closed part, and about 65 mm to about 65 mm from the tip of the closed part. Between 110 mm, a contour line is formed by a straight line parallel to the central axis (S) of the condom. The diameter expands from a position of about 110 mm from the tip of the closed part, becomes the same diameter as the opening near about 135 mm, and a contour line is formed between about 135 mm and the opening by a straight line that is almost parallel to the axial direction of the condom. It is connected to the vicinity of the opening.

(Example 2)
The condoms produced in the above Examples and Comparative Examples were tested for the burst pressure and burst capacity of the condoms by the methods shown below. The measuring equipment includes a cavity for injecting air, an inner fastener having an expansion function in the outer diameter of the cavity, a support on the upper part of the inner fastener, and an outer clamp attached to the outside of the inner fastener. Those having an accessory were used. First, cover the unwound condom on the support rod of the measuring device, sandwich the specified length part of the condom with the inner and outer fasteners, inflate the inner and outer fasteners, and then tighten the inner and outer fasteners. The condom was fixed by the tool. Next, air was injected into the condom, the specified length portion of the condom was inflated with air, and the burst pressure and burst capacity at the time of burst were recorded.

The length of the support rod is defined by the standard. A condom tested using a support rod (125 rod) designed to swell with a length of 125 ± 2 mm excluding protrusions (semen reservoir) based on the Japanese Industrial Standards (JIS), and the International Organization for Standardization (ISO) Measurement of burst pressure and burst capacity obtained for condoms tested using a support rod (150 rod) designed to swell 150 ± 3 mm in length excluding protrusions (semen reservoir) based on the standard). The results are shown in Table 1.

From Table 1, the condom of Example 1 has an improved burst pressure (representing pressure resistance) as compared with the condoms of Comparative Examples 1 and 2, and the burst capacity (corresponding to the accommodating capacity) is the condom of Comparative Example 2. It can be seen that it is larger than that of Comparative Example 1 and maintains a burst capacity close to that of Comparative Example 1.

Claims (6)

An elastically deformable tubular container having an opening, a closed portion with a closed tip, and an intermediate portion connecting the opening and the closed portion, and the intermediate portion has a reduced diameter portion whose diameter is gradually reduced. The diameter of the portion where the diameter of the reduced diameter portion is most reduced is 70 to 95% of the diameter of the portion having the largest diameter of the container, and the vertical cross-sectional shape passing through the central axis of the reduced diameter portion is straight. Elastically deformable, formed by two or more curves that are continuous without a portion, or formed by two or more curves that include one or more straight portions, the straight portion forming a tangent to the curve. Cylindrical container. The tubular container according to claim 1, wherein the vertical cross-sectional shape passing through the central axis of the reduced diameter portion is formed by connecting two or more arcs at inflection points. A first arc that is convex to the outside of the container, a second arc that is convex to the inside of the container, and a third arc that is convex to the outside of the container, which are arranged continuously, are adjacent arcs. The tubular container according to claim 1 or 2, wherein a vertical cross-sectional shape passing through the central axis of the reduced diameter portion is formed by connecting at an inflection point. A first arc that is convex to the outside of the container, a second arc that is convex to the inside of the container, and a third arc that is convex to the outside of the container, which are arranged continuously, are adjacent arcs. The tubular container according to claim 1, wherein a vertical cross-sectional shape passing through the central axis of the reduced diameter portion is formed by connecting via a straight line portion and forming a tangent line with an arc adjacent to the straight line portion. .. In the vertical cross-sectional shape of the container, the ratio (R /) of the radius (R) of the arc forming the portion where the diameter of the reduced diameter portion is most reduced to the diameter (d) of the portion where the diameter of the reduced diameter portion is most reduced. The tubular container according to any one of claims 1 to 4, wherein d) is 8 to 25. The tubular container according to any one of claims 1 to 5, wherein the tubular container is a condom.

Images